class Order {
    orderid!:number
    ordername!:string
    static count:number
    printOrd(){}
    static getCount(){}
}

type OrdInstanceAttrNames=keyof Order
console.log()

type ObjTyp = { username: string; age: 23 }
type ObjKeysType= keyof ObjTyp // "username" | "age"

// 不使用泛型找感觉
function identity(arg: any):any {
    return arg
}

function identity2<T>(arg:T):T {
    return arg
}
let output = identity2<number>(2)
console.log('output',output);

interface Lengthwise {
    length: string;
}
function loggingIdentity<T extends Lengthwise>(arg: T):T {
    return arg
}

loggingIdentity({length:'123456',value:3})

export {}